The Synergy was developed out of the GDS system (in fact you needed a GDS to program). Here is the full story:
"'The GDS came out of some early research at Bell Laboratories in the early '70s,' explains Mercer 'Stoney' Stockell, who himself shared in developing the GDS and Synergy. 'Hal Alles, a researcher there, designed the high-speed additive engine that was put into the GDS and later systems. He was a very bright man. The work originally came out of some stuff he was supposed to be doing for echo-cancellation on telephone lines.'
"'After Hal developed the oscillator [the afore mentioned high speed additive engine], people from both the music industry and other research areas decided that they wanted to do some neat things with it. One interested party was Music Technology [MTI], a division of the Italian company Crumar.... They realized that the technology had a ten-year leap on other musical products of the time, things like the Prophet-5. So they wanted to get this technology out of Bell Labs.' [Bell Laboratories was a non-profit organization and could not sell their designs.]
"After enlisting Hal Alles as an advisor, MTI hired a development staff comprising Stockell, Kevin Doren, Wing Moi, and Jerry Kaplan. 'All of us really had different types of expertise,' says Stockell, 'but we weren't very well organized. We were located in the back of this warehouse. Ernie Briefel and his son Dennis, who now has a company called Music Industries, were very supportive of the project, probably to a fault, which is why Music Technologies is no here anymore... or a contributing factor anyway. They put a lot of time, effort, and money into this project and we built this thing called the GDS.'
"With their development system up and running, the Music Technologies team - er, now Digital Keyboards - focused on the less expensive system. 'Next we came out with this instrument called the Synergy,' Stockell reveals. 'The Synergy was a push-button machine and it didn't offer any programming like the GDS....'"
"When MTI shut down the DK division in the first quarter of 1985, Stockell teamed up with Jim wright and Jerry Ptascynski (pronounced Zan' ski) to form Mulogix. Their lone project was the Slave 32, which was basically a Synergy squeezed into a two-spaced rack-mount module with an improved MIDI implementation. The Slave 32 could play sounds off the Synergy cartridges.... "
[excerpted with permission from the book Vintage Synthesizers by Mark Vail, copyright Miller Freeman, Inc]